Experience in international clinical research: the HIV Prevention Trials Network

Assessing Direct and Spillover Effects of Intervention Packages in Network-randomized Studies

BACKGROUND

Intervention packages may result in a greater public health impact than single interventions. Understanding the separate impact of each component on the overall package effectiveness can improve intervention delivery.

METHODS

We adapted an approach to evaluate the effects of a time-varying intervention package in a network-randomized study. In some network-randomized studies, only a subset of participants in exposed networks receive the intervention themselves. The spillover effect contrasts average potential outcomes if a person was not exposed to themselves under intervention in the network versus no intervention in a control network. We estimated the effects of components of the intervention package in HIV Prevention Trials Network 037, a Phase III network-randomized HIV prevention trial among people who inject drugs and their risk networks using marginal structural models to adjust for time-varying confounding. The index participant in an intervention network received a peer education intervention initially at baseline, then boosters at 6 and 12 months. All participants were followed to ascertain HIV risk behaviors.

RESULTS

There were 560 participants with at least one follow-up visit, 48% of whom were randomized to the intervention, and 1,598 participant visits were observed. The spillover effect of the boosters in the presence of initial peer education training was a 39% rate reduction (rate ratio = 0.61; 95% confidence interval = 0.43, 0.87).

CONCLUSIONS

These methods will be useful for evaluating intervention packages in studies with network features.

Editorial: Forty Years of Waiting for Prevention and Cure of HIV Infection - Ongoing Challenges and Hopes for Vaccine Development and Overcoming Antiretroviral Drug Resistance

In April 1984, 40 years ago, the Secretary of the US Department of Health and Human Services announced that Dr. Robert Gallo and his colleagues at the National Cancer Institute (NCI) had confirmed the cause of acquired immunodeficiency syndrome (AIDS) as a retrovirus, which became known as human immunodeficiency virus (HIV) in 1986. For the past 40 years, prevention and cure of HIV infection have been the dual 'holy grail' sought but still not achieved. By the beginning of 2024, the World Health Organization (WHO) estimated that in the past 40 years, between 65.0 million and 113.0 million people have been infected with HIV, and between 32.9 million and 51.3 million people have died from HIV infection. On 29 February 2024, the WHO published an updated report in response to increasing reports of HIV drug resistance (HIVDR). Currently, HIV vaccines in development are in early-stage clinical trials. People with HIV are more likely to develop tuberculosis, with increasing rates of antimicrobial resistance. MTBVAC is the first live attenuated vaccine to prevent Mycobacterium tuberculosis infection, with phase 2a safety and efficacy clinical trial data expected at the end of 2024. This editorial aims to summarize the current challenges and hopes for developing vaccines to prevent HIV infection and approaches to overcome antiretroviral drug resistance as a cure for HIV/AIDS.

Assessing Direct and Spillover Effects of Intervention Packages in Network-Randomized Studies

Intervention packages may result in a greater public health impact than single interventions. Understanding the separate impact of each component in the overall package effectiveness can improve intervention delivery. We adapted an approach to evaluate the effects of a time-varying intervention package in a network-randomized study. In some network-randomized studies, only a subset of participants in exposed networks receive the intervention themselves. The spillover effect contrasts average potential outcomes if a person was not exposed themselves under intervention in the network versus no intervention in a control network. We estimated effects of components of the intervention package in HIV Prevention Trials Network 037, a Phase III network-randomized HIV prevention trial among people who inject drugs and their risk networks using Marginal Structural Models to adjust for time-varying confounding. The index participant in an intervention network received a peer education intervention initially at baseline, then boosters at 6 and 12 months. All participants were followed to ascertain HIV risk behaviors. There were 560 participants with at least one follow-up visit, 48% of whom were randomized to the intervention, and 1,598 participant-visits were observed. The spillover effect of the boosters in the presence of initial peer education training was a 39% rate reduction (Rate Ratio = 0.61; 95% confidence interval= 0.43, 0.87). These methods will be useful to evaluate intervention packages in studies with network features.

"You Are on the Right Track With the App:" Qualitative Analysis of Mobile Phone Use and User Feedback Regarding Mobile Phone Sexual Risk Assessments for HIV Prevention Research

Background: Accurate self-report of sexual behavior assists in identifying potential HIV exposure in HIV prevention trials. Brief mobile phone assessments, completed daily or after sexual activity, can improve the validity and reliability of self-reported sexual behavior and allow for remote survey completion outside of the clinic setting. We conducted a qualitative study to better understand participants mobile phone use and to explore their perspectives on how to improve an existing mobile application-based sexual risk assessment.

Methods: Sexually active, HIV seronegative men (n = 14) and women (n = 15) aged 18–39 years were recruited through an HIV counseling and testing clinic and community outreach in Soweto, South Africa. We conducted qualitative research through four age-stratified focus group discussions (FGDs) and analyzed a brief socio-demographics and mobile phone access questionnaire. All participants completed a sexual risk assessment before the FGD. Using a framework analytic approach, data were coded with Nvivo software.

Results: All participants had access to mobile phones and internet, and 27 (93.1%) were able to download applications on their personal phones. Participants preferred mobile risk assessments to be offered in a choice of South African languages, using formal language (as opposed to emojis), with straight-forward wording and limited to five to 10 questions. Most participants found it acceptable to complete the assessment once a week, on a weekday, while a few were willing to complete it after each sexual encounter. It was suggested that a message reminder to complete the assessment should be sent at least daily until it is completed. The majority agreed that a password-protected application with a discreet logo was ideal for privacy, ease of use and flexibility for completion in any setting. A concern with this format, however, was the potential data use requirement. Participants expressed privacy concerns with using SMS, WhatsApp and other social media for risk assessments. Most agreed on an airtime incentive between ZAR5-10 (USD 0.29–0.58) per survey. Participants encouraged researchers to provide feedback to them about their sexual risk.

Conclusions: Completion of mobile phone sexual risk assessments can be optimized with minimal incentives by ensuring that questionnaires are simple, brief, infrequent and have trusted privacy measures.

Assessing Individual and Disseminated Effects in Network-Randomized Studies

Implementation trials often involve clustering via risk networks, where only some participants directly receive the intervention. The individual effect is that among directly treated persons beyond being in an intervention network; the disseminated effect is that among persons engaged with those directly treated. In this article, we employ a causal inference framework and discuss assumptions and estimators for individual and disseminated effects and apply them to the HIV Prevention Trials Network 037 Study. HIV Prevention Trials Network 037 was a phase III, network-level, randomized controlled human immunodeficiency virus (HIV) prevention trial conducted in the United States and Thailand from 2002 to 2006 that recruited injection drug users, who were assigned to either an intervention group or a control group, and their risk network members, who received no direct intervention. Combining individual and disseminated effects, we observed a 35% composite rate reduction in the adjusted model (risk ratio = 0.65, 95% confidence interval: 0.47, 0.90). Methodology is now available for estimating the full set of these effects, enhancing knowledge gained from network-randomized trials. Although the overall effect gains validity from network randomization, we show that it will generally be less than the composite effect. Additionally, if only index participants benefit from the intervention, as the network size increases, the overall effect tends toward the null-an unfortunate and misleading conclusion.

Recruitment of Underrepresented Minority Researchers into HIV Prevention Research: The HIV Prevention Trials Network Scholars Program

Most U.S. investigators in the HIV Prevention Trials Network (HPTN) have been of majority race/ethnicity and sexual orientation. Research participants, in contrast, have been disproportionately from racial/ethnic minorities and men who have sex with men (MSM), reflecting the U.S. epidemic. We initiated and subsequently evaluated the HPTN Scholars Program that mentors early career investigators from underrepresented minority groups. Scholars were affiliated with the HPTN for 12-18 months, mentored by a senior researcher to analyze HPTN study data. Participation in scientific committees, trainings, protocol teams, and advisory groups was facilitated, followed by evaluative exit surveys. Twenty-six trainees have produced 17 peer-reviewed articles to date. Research topics typically explored health disparities and HIV prevention among black and Hispanic MSM and at-risk black women. Most scholars (81% in the first five cohorts) continued HIV research after program completion. Alumni reported program-related career benefits and subsequent funding successes. Their feedback also suggested that we must improve the scholars' abilities to engage new research protocols that are developed within the network. Mentored engagement can nurture the professional development of young researchers from racial/ethnic and sexual minority communities. Minority scientists can benefit from training and mentoring within research consortia, whereas the network research benefits from perspectives of underrepresented minority scientists.

Outcome of Sentinel Hospital-based and CDC-based ART Service Delivery: A Prospective Open Cohort of People Living with HIV in China

The primary objective of this study was to obtain insights into the outcomes of people living with HIV who accessed services through HIV/AIDS sentinel hospital-based and ART service delivery in China. Post-hoc analyses of an open cohort from an observational database of 22 qualified HIV/AIDS sentinel hospital-based and two CDC-based drug delivery facilities (DDFs) in Guangdong Province was completed. Linkage to care, mortality and survival rates were calculated according to WHO criteria. 12,966 individuals received ART from HIV/AIDS sentinel hospitals and 1,919 from DDFs, with linkage to care rates of 80.7% and 79.9%, respectively (P > 0.05). Retention rates were 94.1% and 84.0% in sentinel hospitals and DDFs, respectively (P < 0.01). Excess mortality was 1.4 deaths/100 person-years (95% CI: 1.1, 1.8) in DDFs compared to 0.4 deaths/100 person-years (95% CI: 0.3, 0.5) in hospitals (P < 0.01). A Cox-regression analysis revealed that mortality was much higher in patients receiving ART from the DDFs than sentinel hospitals, with an adjusted HR of 3.3 (95% CI: 2.3, 4.6). A crude HR of treatment termination in DDFs was 7.5 fold higher (95% CI: 6.3, 9.0) compared to sentinel hospitals. HIV/AIDS sentinel hospital had better retention, and substantially lower mortality compared to DDFs.

Differential Globalization of Industry- and Non-Industry-Sponsored Clinical Trials

BACKGROUND

Mapping the international landscape of clinical trials may inform global health research governance, but no large-scale data are available. Industry or non-industry sponsorship may have a major influence in this mapping. We aimed to map the global landscape of industry- and non-industry-sponsored clinical trials and its evolution over time.

METHODS

We analyzed clinical trials initiated between 2006 and 2013 and registered in the WHO International Clinical Trials Registry Platform (ICTRP). We mapped single-country and international trials by World Bank's income groups and by sponsorship (industry- vs. non- industry), including its evolution over time from 2006 to 2012. We identified clusters of countries that collaborated significantly more than expected in industry- and non-industry-sponsored international trials.

RESULTS

119,679 clinical trials conducted in 177 countries were analysed. The median number of trials per million inhabitants in high-income countries was 100 times that in low-income countries (116.0 vs. 1.1). Industry sponsors were involved in three times more trials per million inhabitants than non-industry sponsors in high-income countries (75.0 vs. 24.5) and in ten times fewer trials in low- income countries (0.08 vs. 1.08). Among industry- and non-industry-sponsored trials, 30.3% and 3.2% were international, respectively. In the industry-sponsored network of collaboration, Eastern European and South American countries collaborated more than expected; in the non-industry-sponsored network, collaboration among Scandinavian countries was overrepresented. Industry-sponsored international trials became more inter-continental with time between 2006 and 2012 (from 54.8% to 67.3%) as compared with non-industry-sponsored trials (from 42.4% to 37.2%).

CONCLUSIONS

Based on trials registered in the WHO ICTRP we documented a substantial gap between the globalization of industry- and non-industry-sponsored clinical research. Only 3% of academic trials but 30% of industry trials are international. The latter appeared to be conducted in preferentially selected countries.

Antiretrovirals for HIV prevention: when should they be recommended?

Since the introduction of the first antiretroviral agent for HIV treatment, information on antiretroviral therapy (ART) effectiveness has grown continuously. In recent years, there has also been a growth of interest in use of ART for the prevention of HIV transmission, either by reducing the infectivity of the infected person or by protecting the uninfected individuals from HIV acquisition. The purpose of this review is to summarize the body of evidence available for treatment as prevention and pre-exposure prophylaxis and their effectiveness in prevention of infection. In addition, our aim is to discuss the operational aspects of both prevention strategies and to provide commentary for future HIV prevention programs.

Early phase clinical trials with human immunodeficiency virus-1 and malaria vectored vaccines in The Gambia: frontline challenges in study design and implementation

Human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) and malaria are among the most important infectious diseases in developing countries. Existing control strategies are unlikely to curtail these diseases in the absence of efficacious vaccines. Testing of HIV and malaria vaccines candidates start with early phase trials that are increasingly being conducted in developing countries where the burden of the diseases is high. Unique challenges, which affect planning and implementation of vaccine trials according to internationally accepted standards have thus been identified. In this review, we highlight specific challenges encountered during two early phase trials of novel HIV-1 and malaria vectored vaccine candidates conducted in The Gambia and how some of these issues were pragmatically addressed. We hope our experience will be useful for key study personnel involved in day-to-day running of similar clinical trials. It may also guide future design and implementation of vaccine trials in resource-constrained settings.

High HIV incidence among persons who inject drugs in Pakistan: greater risk with needle sharing and injecting frequently among the homeless

Background

The incidence of HIV among persons who inject drugs (PWIDU) has fallen in many nations, likely due to successes of clean needle/syringe exchange and substance abuse treatment and service programs. However in Pakistan, prevalence rates for PWID have risen dramatically. In several cities, prevalence exceeded 20% by 2009 compared to a 2003 baseline of just 0.5%. However, no cohort study of PWID has ever been conducted.

Methods

We enrolled a cohort of 636 HIV seronegative PWID registered with three drop-in centers that focus on risk reduction and basic social services in Karachi. Recruitment began in 2009 (March to June) and PWID were followed for two years. We measured incidence rates and risk factors associated with HIV seroconversion.

Results

Incidence of HIV was 12.4 per 100 person-years (95% exact Poisson confidence interval [CI]: 10.3–14.9). We followed 474 of 636 HIV seronegative persons (74.5%) for two years, an annual loss to follow-up of <13 per 100 person years. In multivariable Cox regression analysis, HIV seroconversion was associated with non-Muslim religion (Adjusted risk ratio [ARR] = 1.7, 95%CI:1.4, 2.7, p = 0.03), sharing of syringes (ARR = 2.3, 95%CI:1.5, 3.3, p<0.0001), being homeless (ARR = 1.7, 95%CI:1.1, 2.5, p = 0.009), and daily injection of drugs (ARR = 1.1, 95%CI:1.0, 1.3, p = 0.04).

Conclusions

Even though all members of the cohort of PWID were attending risk reduction programs, the HIV incidence rate was very high in Karachi from 2009–2011. The project budget was low, yet we were able to retain three-quarters of the population over two years. Absence of opiate substitution therapy and incomplete needle/syringe exchange coverage undermines success in HIV risk reduction.

The role of men as partners and fathers in the prevention of mother-to-child transmission of HIV and in the promotion of sexual and reproductive health

Despite ample evidence documenting the positive impact of men on the prevention of mother-to-child transmission (PMTCT) and other sexual and reproductive health programs, men's engagement remains very low. This paper examines the current level and nature of male involvement and identifies opportunities for the advancement of men's constructive engagement in PMTCT and sexual and reproductive health. Conceptual and policy barriers have encouraged the inadvertent exclusion of men from PMTCT and other reproductive health services. The historic institutionalization of reproductive health as women's health has generally resulted in health services that are not welcoming of men and has undermined efforts to engage couples. This paper argues that to maximize the health outcomes of PMTCT and sexual and reproductive health programs for women and men, we must move beyond seeing men as simply "facilitating factors" that enable women to access health-care services. Men need to instead be recognized as a constituent part of reproductive health policy and practice. The paper proposes strategies for policy makers and program leaders to engage men and couples to foster communication and shared decision-making. This approach can both help to achieve health goals and engender more equitable relationships between men and women.

Translation of biomedical prevention strategies for HIV: prospects and pitfalls

Early achievements in biomedical approaches for HIV prevention included physical barriers (condoms), clean injection equipment (both for medical use and for injection drug users), blood and blood product safety, and prevention of mother-to-child transmission. In recent years, antiretroviral drugs to reduce the risk of transmission (when the infected person takes the medicines; treatment as prevention) or reduce the risk of acquisition (when the seronegative person takes them; preexposure prophylaxis) have proven to be efficacious. Circumcision of men has also been a major tool relevant for higher prevalence regions such as sub-Saharan Africa. Well-established prevention strategies in the control of sexually transmitted diseases and tuberculosis are highly relevant for HIV (ie, screening, linkage to care, early treatment, and contact tracing). Unfortunately, only slow progress is being made in some available HIV-prevention strategies such as family planning for HIV-infected women who do not want more children and prevention of mother-to-child HIV transmission. Current studies seek to integrate strategies into approaches that combine biomedical, behavioral, and structural methods to achieve prevention synergies. This review identifies the major biomedical approaches demonstrated to be efficacious that are now available. We also highlight the need for behavioral risk reduction and adherence as essential components of any biomedical approach.